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Abstract:

A computerized method is provided for designing a vent in a hearing aid
housing shell based on an image of a patient's ear canal impression, and
wherein a program is provided on a computer-readable medium. With the
program, an image of a starter housing shell based on the image of the
patient's ear canal impression is created which is longer than a final
version of the housing shell to be created. A starter vent running from
an inner canal end near the patient's ear drum to an outer end of the
starter housing shell is placed inside the shell. Components are then
placed substantially as deep as possible inside the starter shell but
lying outside of the starter vent. Portions of the starter shell lying
beyond where a faceplate is to be mounted are removed and the faceplate
is mounted. The starter vent is then grown larger so that it fills
substantially all space inside the shell without interfering with the
components.

Claims:

1. A computerized method for designing a vent in a hearing aid housing
shell based on an image of a patient's ear canal and wherein a program is
provided on a computer-readable medium run on a computer, said program
performing the steps of:creating an image of a starter housing shell
based on the patient's ear canal impression which is longer than a final
version of the housing shell to be created;placing a starter vent inside
the starter shell and running from an inner canal end near the patient's
ear drum to an outer end of the starter shell;placing components
substantially as deep as possible inside the shell but lying outside of
the starter vent;removing portions of the starter shell beyond where the
faceplate is to be mounted and mounting the faceplate; andgrowing the
starter vent larger so that it fills substantially all space inside the
shell without interfering with said components.

3. A method of claim 1 wherein the vent which is grown larger has its one
end at said inner canal end of the housing shell defined by a first cut
plane and the end at the faceplate defined by a second cut plane.

4. A method of claim 3 wherein said first cut plane is approximately a 45
degree cut with respect to a plane of a faceplate at the faceplate end
and said second cut plane is a cut resulting in a slight slope next to an
edge of said faceplate at said faceplate end of the housing shell.

5. A method of claim 1 wherein the components inside the shell comprise a
receiver having a receiver tube connected thereto extending to a receiver
hole at said inner canal end of the housing shell and wherein said
receiver hole lies adjacent to an end of the vent at said shell inner
canal end.

6. A method of claim 1 wherein prior to growing the starter vent larger,
the housing shell at said faceplate end is adapted to receive a
faceplate.

7. A method of claim 1 wherein the starter vent is placed before placing
the components in the starter housing shell.

8. A method of claim 1 wherein a shape of the housing shell at the
faceplate end is shaped for the faceplate before final component
placement but after placement of the starter vent.

9. A method of claim 1 wherein to create the image of the starter housing
shell, the patient ear impression is defined by a point cloud and then
utilizing adjacent three points of the point cloud a continuous surface
is defined for the housing shell.

10. A method of claim 1 wherein the components which are not part of the
faceplate lie in a free space along side a separator wall partially
defining the vent.

11. A computer-readable medium comprising a program for designing a vent
in a hearing aid housing shell based on an image of a patient's ear
canal, said program performing the steps of:creating an image of a
starter housing shell based on the patient's ear canal impression which
is larger than a final version of the housing shell to be created;placing
a starter vent inside the starter shell running from an inner canal end
near the patient's ear drum to an outer end of the starter shell;placing
components substantially as deep as possible inside the shell but lying
outside of the starter vent;removing portions of the starter shell beyond
where the faceplate is to be mounted and mounting the faceplate;
andgrowing the starter vent larger so that it fills substantially all
space inside the shell without interfering with said components.

12. A computerized method for designing a vent in a hearing aid housing
shell based on an image of a patient's ear canal and wherein a program is
provided on a computer-readable medium run on a computer, said program
performing the steps of:creating an image of the housing shell based on
the patient's ear canal impression;placing a starter vent running from an
inner canal end near the patient's ear drum to a faceplate end of the
housing shell;placing components inside the shell lying outside of the
starter vent; andgrowing the starter vent larger so that it fills
substantially all space inside the shell without interfering with said
components.

Description:

BACKGROUND

[0001]A vent (also referenced to herein as a "venting channel") is an
important part of a hearing aid. A vent is required to provide air
circulation and minimize occlusion. If a vent is not provided, a user
will likely have an uneasy feeling caused by an unequal pressure
differential present in a space between the users ear drum and an inner
ear canal end of the hearing aid housing compared to the atmospheric
pressure external to the hearing aid housing outwardly of the ear. Users
have described this uneasy feeling as an unnatural pressure differential.
Users have also complained of what has been described as an unnatural
hollow sound when the hearing aid is used if no vent is provided.
Furthermore, care must be given in choosing the size of the vent since if
the vent is too large, undesirable acoustic feedback may occur. When
marketing experts in the hearing aid industry are asked which shell they
would consider ideal, many of them will indicate a shell as small as
possible, but with a vent as big as possible. The term "shell" used
herein means an outermost wall of the hearing aid housing.

[0002]A "collection vent" is a known prior art vent in hearing aids which
starts as a regular round vent at a faceplate outer side of the hearing
aid (also called a "starter vent" hereafter) and continues some distance
as a round vent and then increases in diameter gradually until some size
specified by a designer and which terminates at the canal side of the
hearing aid near the ear drum.

SUMMARY

[0003]It is an object to provide an automated software design method for a
hearing aid which designs a vent-as-large-as-possible, and which takes as
much space as possible in a housing shell of the hearing aid.

[0004]A computerized method is provided for designing a vent in a hearing
aid housing shell based on an image of a patient's ear canal impression,
and wherein a program is provided on a computer-readable medium. With the
program, an image of a starter housing shell based on the image of the
patient's ear canal impression is created which is longer than a final
version of the housing shell to be created. A starter vent running from
an inner canal end near the patient's ear drum to an outer end of the
starter housing shell is placed inside the shell. Components are then
placed substantially as deep as possible inside the starter shell but
lying outside of the starter vent. Portions of the starter shell lying
beyond where a faceplate is to be mounted are removed and the faceplate
is mounted. The starter vent is then grown larger so that it fills
substantially all space inside the shell without interfering with the
components.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005]FIG. 1 is a flow chart of software in the computer for automatic
creation of an optimized venting channel (vent) in a hearing aid
instrument;

[0006]FIG. 2 is a perspective view of the hearing aid showing an outer
housing shell and an outer end of a vent-as-large-as-possible running
through the hearing aid;

[0007]FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2
showing a side profile of the hearing aid housing shell of FIG. 2;

[0008]FIG. 4 is a side perspective view of the hearing aid housing shell
of FIG. 2;

[0009]FIG. 5 is a cross-sectional view taken along line V-V of FIG. 3
showing a portion of the vent-as-large-as-possible at the cross-section;
and

[0010]FIG. 6 is a table showing vertically shell type and horizontally
maximal and minimal cross-section size of the vent-as-large-as-possible
for different shell types.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0011]For the purposes of promoting an understanding of the principles of
the invention, reference will now be made to the preferred embodiment
illustrated in the drawings and specific language will be used to
describe the same. It will nevertheless be understood that no limitation
of the scope of the invention is thereby intended, and such alterations
and further modifications in the illustrated device and such further
applications of the principles of the invention as illustrated as would
normally occur to one skilled in the art to which the invention relates
are included.

[0012]When the term "venting channel" or "vent" is used hereafter, it
means a structure inside the shell that permits air flow between the
inner ear canal near the ear drum and the outside atmosphere where the
user is located.

[0013]When the acronym CIC is used hereafter, it means
completely-in-the-canal.

[0014]A main goal is to provide an automated software design method which
provides a vent of a biggest possible size, while having the shell of the
hearing aid of a smallest possible size. A size of the shell is a more
important constraint than a size of the vent. A big vent is desired by a
patient to improve air circulation in the ear and to minimize the
occlusion effect. The occlusion effect is minimized as the vent acoustic
mass is decreased.

[0015]The vent designed by the present software techniques of the
preferred embodiment is hereinafter known as the
"vent-as-large-as-possible" and alternately is also referred to as a
"size-maximized vent".

[0016]In a vent designed as-large-as-possible the occlusion effect is
comprised of two major sub-functionalities:

[0017]1. building the vent-as-large-as-possible for a given location of
the components; and

[0018]2. insuring insertability of components principally including a
receiver in the shell.

[0019]The receiver 7 and other components 5 are located in the housing
shell as shown in FIG. 3 and discussed hereafter. The receiver emits
sound into the ear of the patient via a receiver tube 7A which runs from
a receiver spout 7B of the receiver 7 where sound exits the receiver 7,
and runs from there to a receiver hole 6, which is a hole on the shell 8
close to an end 18A of the vent 18 at an innermost end of the housing
shell near the ear drum as shown in FIG. 3.

[0020]As shown in FIG. 1, a flow chart 9 is provided for the automatic
creation of an optimized venting channel (vent) in the hearing instrument
by use of software run in a computer. In the first block 10, LOAD WORK
ORDER, an order entry is received from a customer. A physical impression
of a patient's ear canal is converted to a so-called "point cloud", which
is a computer image data file of points on an outside surface of the
physical impression. This point cloud data file is then loaded into the
computer at block 10. At block 117 "DETAIL CANAL AND CREATE STARTER
SHELL", from the point cloud data file a surface file is created by use
of a plurality of triangles defined by adjacent point cloud triplets.
This surface file describes a continuous outer surface of a starter
version of the housing shell 8 (see FIGS. 2, 3). Unnecessary material is
removed from the canal area of the end 8A of the shell near the ear
canal.

[0021]At block 12, "BUILD THE REGULAR ROUND VENT OF A MINIMAL
CROSS-SECTION AS A STARTER VENT IN THE STARTER SHELL" the computer
constructs an initial vent or what is known hereafter as a "starter" vent
3 which is preferably substantially round in cross-section of relatively
small dimensions and runs from the end 8A of the starter shell 8 (FIGS.
2, 3) nearest the ear drum to a starter end 8BB lying beyond the outer
end 8B of the shell (see FIGS. 2, 3) where what is known as a faceplate
16 (FIGS. 2, 3, and 4) is to be mounted in a later step. This regular
round vent 3 is of an initial minimal size and represents a starting
point for the software construction (starter vent).

[0022]In block 13, "GO BACK TO DETAILING AND SHAPE THE STARTER SHELL
AROUND WHERE THE FACEPLATE WILL BE MOUNTED USING VENT PREVIEW", a shape
of an outer end 8B of the shell where the faceplate 16 is to be provided
is designed. As shown in FIGS. 2, 3, the faceplate 16 glued on the shell
will have an edge 16B adjacent to and defining one side of an aperture at
an outer end 18B of the vent 18 open to the atmosphere, along with a trap
door 19 with a finger-nail lift tab 19A which swings open for access to a
battery. Other components such as a volume control and a push button, and
a microphone opening 20 are mounted on the faceplate. Note that the
faceplate may contain or have mounted on it also other controls besides
the microphone: push buttons, volume control, etc. Components including a
hybrid, telecoil, reed switch, and an electronics module 5 with battery
are provided in a free space 21 (see FIG. 3) exterior to the vent 18
defined by vent wall 18C. The electronics module may be part of the
faceplate or attached directly below it in space 21. The receiver 7 is
also provided down further inside the housing shell in the free space 21.

[0023]In block 13, the continuous shell surface is created using the
previously mentioned triangulation technique Material is also removed
near the area where the faceplate is to be mounted to provide room for an
opening for the vent and components to be mounted on the faceplate.

[0024]In block 14, "GO TO THE COMPONENTS STEP AND FINALIZE LOCATION OF
COMPONENTS AS DEEP AS POSSIBLE IN THE STARTER SHELL", the program does
what is necessary to push the components as deep as possible into the
starter housing shell without interfering with the starter vent 3.

[0025]At block 15, "REMOVE PORTIONS OF THE STARTER SHELL BEYOND WHERE THE
FACEPLATE IS TO BE MOUNTED AND MOUNTING THE FACEPLATE", a starter shell
portion 4 having starter shell end 8BB beyond where the faceplate 16 is
to be located are removed and the faceplate 16 is mounted.

[0026]At block 160, "GO TO THE NEXT STEP AND LET VENT TAKE UP
SUBSTANTIALLY ALL FREE SPACE AVAILABLE TO CREATE THE VENT-AS-LARGE-AS
POSSIBLE", an algorithm looks at the shell 8, the location of the
components, and the location of the minimal round vent, and increases a
size of the starter vent 3 defined by wall 18C so that it occupies the
space substantially not occupied by the components such as module 5 and
the receiver 7 with receiver tube 7A which are situated in free space 21
inside the shell 8 (see FIGS. 2, 3). The thus maximized vent 18 is shown
by the vent wall 18C contour in FIG. 3. Note also that the vent wall 18C
at a central region of the shell is part of a separating wall 18CC
separating the vent-as-large-as-possible 18 from the free space 21. Also
note that the receiver tube 7A running from the receiver 7 down to the
canal end 8A of the shell near the ear drum lies just outside the
separator wall 18CC partially defining the vent-as-large-as possible 18.
Also note electronic cable 7D from electronics module 5 running down to
the receiver 7.

[0027]In block 170, "SELECTIVE FILL AND LABELING", a selective fill and/or
labeling is processed. Fill material is shown in FIG. 3 at the
cross-hatched regions 23. Note that selective fill and labeling are
optional steps, and therefore can be skipped.

[0028]FIGS. 2 and 3 show the vent-as-large-as-possible at 18. At the canal
side end 8B of the shell 8, for the vent-as-large-as-possible 18 (nearest
the eardrum) an operator of the software does a cut to create a cut plane
22 identical to a cut currently performed for the known collection vent
(regular round vent) previously described. On the faceplate side of the
vent-as-large-as-possible shell, the operator does another cut to create
another cut plane 23 in order to accommodate the large outlet end 188 of
the vent-as-large-as possible 18. Here the faceplate 16 has side edge 16B
defining one side of the vent 18 aperture at the end 18B. This is shown
in FIGS. 2 and 3.

[0029]FIG. 3 will now be described in more detail. FIG. 3 shows the
housing shell 8 with the end 8A closest to the ear drum at the bottom and
the end 8B at the faceplate 16 at the top after removal of the portion 4
(shown in dashed lines) of the starter shell 8. Components of the hearing
aid such as the electronics module 5 are shown in this drawing figure in
space 21. The 45 degree cut plane 22 is provided on curved surface 19 at
the housing shell canal side 8A at the bottom. The region or free space
21 shows where the electronics module 5 and receiver 7 are to be housed.
The substantially horizontal rectangle panel illustrated at the top is
the faceplate 16. Note that during the shell assembly after the faceplate
is glued to the shell all faceplate material 16A outside of the shell is
trimmed away. The trap door 19 with finger nail protrusion 19A is shown
at the top of the faceplate 16. The two cut planes 22 and 23 are
provided. In the preferred embodiment the first cut plane is the 45
degree cut plane 22 described above, and the second cut plane 23 is shown
at edge 16B of the faceplate 16 at the left side of the drawing and
slanting slightly down from edge 16B. Note that other angles of cuts are
also acceptable. The vent-as-large-as-possible 18 is defined by the vent
wall 18C in FIG. 3 and runs from this second cut plane 23 next to the
edge 16B of the faceplate 16 at the outside end 18B of the vent, down to
the 45 degree cut plane 22, which is the vent end 18A at the canal side
near the eardrum. The top cut plane 23 next to the faceplate 16 at edge
16B is called a low angle cut plane.

[0030]The material shown as cross-hatching in FIG. 3 and exterior to the
vent wall 18C is either part of the housing shell 8 or the separator wall
18CC.

[0031]Where the cut planes are provided depends upon a location of
electronics such as electronics module 5, optional components, receiver
7, receiver hole 6, receiver tube 7A, and values of different preferences
parameters that define a shape of the vent 18, vent end 18A and vent end
18B.

[0032]Vent design for the vent-as-large-as-possible of the preferred
embodiment is very different from vent design for the previously
mentioned prior art collection vent. A main difference is that for the
collection vent design, an algorithm finds just a biggest contour that
can accommodate the vent inlet. In the case of the
vent-as-large-as-possible of the preferred embodiment herein, the vent
inlet contour can be smaller than the vent inlet for the collection vent,
because one needs to avoid collisions with the components and receiver
hole, and adhere to other preferences settings not used for the
collection vent. Another important difference between the existing prior
art vents and the new vent-as-large-as-possible is that prior art vents
are built without any consideration of component positions. The vent is
built first, and then components are placed into the shell in the prior
art. In the vent-as-large-as-possible first the starter vent is placed,
then components such as volume control, push button, receiver,
electronics module with battery, and microphone are placed as deep as
possible in the starter shell, then the starter shell is cut to remove
portions beyond where the faceplate is to be located, and then the
starter vent is transformed into the vent-as-large as possible.

[0033]The shape of the vent end at 18A and vent end at 18B in FIG. 3 is
defined following preferences settings. The term "preferences settings"
means for the design software of the present preferred embodiment, the
particular parameters chosen by the operator defining how different
algorithms in the software perform functions.

[0034]FIG. 4 shows the housing shell 8 oriented with the ear canal end 8A
at the bottom and the faceplate end 8B at the top. This drawing figure
shows the approximate 45 degree cut plane 22 described previously at the
ear canal end 8A and indicates by dashed line 24 with three vertical
slashes 50% of the canal width at the vent end 18A to show where the cut
plane 22 begins for the approximate 45 degree cut.

[0041]5. go to the faceplate mounting step (FIG. 1--block 15) and after
the faceplate mounting step the starter vent (regular round vent--block
12 in FIG. 1) is replaced with the vent-as-large-as-possible (FIG.
1--block 160); and

[0042]6. proceed to a selective fill and/or labeling step (FIG. 1--block
170--a selective fill and labeling) which is selecting an area with a
plane and filling it with material, and the labeling is the step of
assigning an identification for the shell by engraving or embossing on an
inside surface of the shell housing.

[0043]The software method of the preferred embodiment ensures that the
vent-as-large-as-possible takes as much as possible space in the shell
adhering to the constraints provided in the requirements (preference
settings).

[0044]The software provides the ability to place the
vent-as-large-as-possible starter vent (regular round vent) inside the
shell in the following manner:

[0045]A. a starter section (regular round vent) is equal to a minimal
cross-section area of the vent-as-large-as-possible defined in the
preferences--for example if the minimal cross-section area as defined in
the preferences is S, then a radius of a regular round vent is computed
from the formula S=PI*r 2, where r is the radius of the regular vent, and
PI is 3.1415926;

[0046]B. a vent is always shown during a preview in detailing the
vent-as-large-as-possible if the user has already placed the starter vent
(regular round vent);

[0047]C. the software does not show the vent at all during the vent
preview--in detailing the user has not yet placed the starter vent
(regular round vent) for the vent-as-large-as-possible;

[0048]D. the software allows the user to place the starter vent (regular
round vent) during the vent step--the software generates the
vent-as-large-as-possible from the starter vent (regular round vent); and

[0050]The software builds the vent-as-large-as-possible similar to a
collection IROS (an IROS vent is an Ipsolateral Routing of Signal vent):

[0051]A. in the preferences the settings are provided for a maximal
curvature of the vent end 18A wall--the software ensures that the inlet
end 18A wall of the vent-as-large-as-possible does not violate a maximal
curvature of the vent inlet end 18A wall defined in the preferences;

[0052]B. in the preferences the settings are provided for the maximal
curvature of the vent outlet end 18B wall--the software ensures that the
outlet 18B wall of the vent-as-large-as-possible does not violate the
maximal curvature of the vent outlet end 18B wall defined in the
preferences; and

[0053]C. the software builds the vent-as-large-as-possible inside the
shell 8 similarly to a non-continuous D-shape vent as a straight segment
with optional connecting segments--a D-shape vent is a vent which is
built as a wall inside the shell with openings at the faceplate and the
canal side,--normally this vent has a shape of a "D".

[0054]FIG. 5 shows a view of the vent-as-large-as-possible 18 inside the
shell 8 at a cross-section shown in FIG. 3 at section line V-V at a lower
part of the shell 8 near the ear canal end 8A. The receiver 7 is shown
alongside the vent separator wall 18CC in free space 21.

[0055]The software of the preferred embodiment ensures or provides the
following:

[0056]A. that the vent-as-large-as-possible has no collisions with any of
the components (including receiver hole 6);

[0057]B. in the preferences, settings are provided for minimal
cross-section area inside the vent in mm2;

[0058]C. in the preferences, the settings are provided for maximal
cross-section area inside the vent in mm2 ;

[0059]D. in the preferences, different settings are provided for the
vent-as-large-as-possible minimal and maximal cross-section area
depending upon the shell type--this vent-as-large-as-possible minimal
cross-section depending on the shell type is shown in FIG. 6 which shows
a table of shell type indicated vertically and maximal cross-section and
minimal cross-section that the software could adhere to indicated
horizontally;

[0060]E. the vent inlet end 18A and outlet end 18B for the
vent-as-large-as-possible 18 does not go outside the suggested vent inlet
and outlet cut planes 22 and 23;

[0061]F. in the preferences the settings are provided for maximal allowed
absolute gradient of two adjacent vent cross-section areas; and

[0062]G. the vent-as-large-as-possible generation algorithm (FIG. 1--block
160) ensures that an absolute gradient of adjacent vent slice areas is
lower than a preference value--a gradient of adjacent vent slice areas is
calculated as (a2-a1)/d, where a2 and a1 are areas of adjacent
cross-sections, and d is a distance between cross-sections--if the
absolute gradient of adjacent cross-section areas is higher than certain
thresholds than this means that in these particular cross-sections the
vent makes a large bend--it is desirable that the vent be smooth,
therefore with the maximal and minimal ratio one is able to control the
smoothness of the vent.

[0063]The software also provides for the following:

[0064]A. ensures that the hearing aid receiver 7 can be inserted into the
shell 8 up to its final location given the vent-as-large-as-possible 18
placement;

[0065]B. ensures that the vent generation algorithm does not modify a
position of components during the vent-as-large-as-possible 18
integration;

[0066]C. allows the user to apply the vent-as-large-as-possible 18 with
one mouse click, provided that the starter vent (regular round vent) is
already placed--the user interface comprises one button that applies the
vent-as-large-as-possible, or the user may go from the faceplate step
(FIG. 1--block 15) to the selective fill step (FIG. 1--block 170) and the
vent-as-large-as-possible may be applied;

[0067]D. allows the user to remove the vent-as-large-as-possible 18 from
the shell 8 if no other operation has been applied to the shell 8 after
the vent-as-large-as-possible 18 is placed--this can be implemented with
an undo button;

[0068]E. does not allow adaptive vent tapering on the
vent-as-large-as-possible 18 (although the resulting shell 8 of the
vent-as-large-as-possible 18 may look similar on the vent inlet end 18A
side to the adaptive vent tapering);

[0069]F. allows to put into a script file the placement of the
vent-as-large-as-possible 18 starter vent (regular round vent);

[0070]G. allows the user to position the receiver 7, electronics, hybrid
and all optional components prior to the generation of the
vent-as-large-as-possible 18 from the starter vent (regular round
vent)--the user is not allowed to position the receiver 7, electronics,
hybrid and all optional components after the generation of the
vent-as-large-as-possible from the starter vent (regular round vent); and

[0071]H. does not allow the vent-as-large-as-possible 18 in a combination
with RSA (RSA means Receiver Suspension Assembly which is a series of
design steps for receiver placement).

[0072]While a preferred embodiment has been illustrated and described in
detail in the drawings and foregoing description, the same is to be
considered as illustrative and not restrictive in character, it being
understood that only the preferred embodiment has been shown and
described and that all changes and modifications that come within the
spirit of the invention both now or in the future are desired to be
protected